This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. For this Core, one prime function is to provide high level flow cytometric capabilities to analyze progenitor cell populations and progeny based on immunological, genetic, physical, and/or metabolic properties. These capabilities are of importance in working with rare stem and progenitor populations, but also find excellent application in cell and biomedical investigations at-large. Specifically, this Core is equipped with a Becton Dickinson FACS-Calibur flow cytometer that enables 4-color (immuno)staining plus forward and side scatter analyses. It's also coupled to dedicated workstations with high-end software for population analyses at the single-cell level, including cell cycle parameters. Flo-Jo, Win-List and related programs are also supported to facilitate publication-quality graphics of complete cytograms. With the continuing success of our Center (and Institute) highly productive use of our flow cytometry system has increased markedly (to the extent that we've recently applied for Maine state R &D bond funds to purchase a second BD system). For this aspect of Core B, and to allow ES cell as well as FACS and MACS components to develop in parallel with strong initial support, this latter set of facilities and services (ES cell, FACS, MACS) have been re-framed in year-6 (via NCRR approval) as separate-standing Core E. This also has allowed Core B to begin to develop multi-well high-throughput fluorimetry / luminometry (newly acquired modulus system plus injectors) and to make efficient day-to-day use of a versatile Vi-Cell cell analyzer.